Centrifugal governor



c. J. HENDRI CKSON CENTRIFUGAL GOVERNOR- July 17, 1923.

Filed Sept. 28 1921 ment which Patented July 17, 1923.

* um'rsn 'sraras PATENT'OFFICE.

oHARLEsJ. 'HENDRICKSON, or N W YORK, n; 55., ASSIGNOR To WESTERN ELECTRIC: COMPANY, INCORPORATED, on NEW YoRK, n.=Y., A CORPORATION on NEW YORK.

CENTBIFUGAL GOVERNOR.

Application filed September 28, 1921. Serial No. 503,842.

To all/whom it may concern Be it known that 1, CHARLES J. HENDRIOK- SON, a citizen of the United States, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Centrif ugal Governors, of which the following is a full, clear, concise, and exact description.

This invention relates to centrifugal friction retarded governors and its object is the provision. of a governor which will operate up to a predetermined maximum. speed but cannot be forced beyond that speed by the application of additional driving force.

The present invention is particularly, applicable to calling devices such as shown in United States Patent No. 1,161,85 i, issued to O. F. Forsberg November 30, 1915, for use on subscribers telephone sets in automatic telephone systems. Such a device, as is quite generally known, comprises .a rotatable dial which the calling subscriber operates with his finger. The operation con sists, usually, of rotating the dial a variable angular distance until the subscribers finger encounters a stop which is especially provided for the purpose, whereupon. he releases the dial permitting it to return to its normal position. This operation is repeated a number of times corresponding with the number of digits in the called subscribers number, and each time the calling subscriber inserts his finger in a particular finger hold in the dial corresponding with the particular digit, or,,inother words, with thenumberof electrical impulses he desires to send. Upon each return movement of the dual a suitable mechanism is operated whereby the subscribers line circuit is interrupted oneor' .Any appreciable increase above normal inthe rate at which the circuit is interrupted is likely to result in a wrong connection.

It has been found in practice that some subscribers, in spite of instructions to the contrary, try to expedite their connections by forcing the dial in itsb-ackward moveaction instead of accomplishing this object, usually secures a wrong connection.- A number'of attachments for calling dials have heretofore been-proposed to prevent forcing of the dial; but each of them has I added something to the cost ofthe calling device, and for that reason they have not been generally used. I

The present invention accomplishes the'object set forth andadds little or nothing to the cost of theicalling device for the reason that no additional parts are required.

A governor inaccordance with this invention consists preferably of a stationary member having an internal annular surface, and a rotatable member, including pivoted fly-weights, which. are adapted to frictionally engage the internal annular surface of the stationary member when the governor is rotated at its predetermined maximum speed. The fly-weights are preferablyprm vided. with friction studs which are so located with respect to the pivotal points of their respective fly-weights that any force tending to rotate the rotatable'member in addition to such force as is. necessary-to drive the rotatable member at its predetermined maximum speed will be completely or almost completely opposed by the frictional retardingforce offithe governor.

Fora more complete description of the invention,reference will now be had to the accompanying drawing in which Fig. 1.is a

lan view of a governor constructed in accordance with this invention; ,Fig. 2 is a cross sectional view taken along the line 2-2 of Fig. 1 Fig. 3 is a cross-sectionalview of the ratchet mechanismtaken along the line 33 in Fig. 2; and Fig. 4 is a diagrammatic view correspondingwith Fig. 1 illustrating, graphically,the resolution of forces operatin in the governor. a I 7 he structure shownin FigsJl and 2 is somewhat similar to that shown and described in the copending application of Henry F. Dobbin, Serial No. 428,695, filed December 6,. 1920'. It comprises a spindle which is coaxial with and journaled at one end in the stationary cup-shaped member 2 and at the other end in a suitable bearing which is not shown. Pinion 3, is revolubly mounted on spindle 1 and is provided with y no F ly-weights 7 are pivotally mounted on plate 6 by means of'suitable pins 8 and are free to move outwardly in response to centrifugal force. Each fly-weight T is provided with a friction stud 9 which is adapted to engage the internal annular surface of the cup-shaped member 2.

Each fly-weight is also provided with a pliable arm 10, which in the present instance is secured thereto by being inserted in a slot 11 in the fiy-weight. The arms 10 are each shown provided with a pointer 12 which registers with a calibrated scale on its respective fly-weight.

A retractile spring 13 is connected between the pliable arms 10 and passes through an aperture 14 in spindle 1. This spring is intended to oppose the centrifugal force developed in the fly-weights when the governor is operated. By bending either or both of the pliable arms 10 toward the designation F on their respectively asso ciated scales, the tension of spring 13 is in- I creased and accordingly the speed at which 25 the governor will operate is increased. Bending the pliable arms toward their re spective scale designation 6 will, of course, decrease the tension in spring 13 and accordingly the speed at which the governor may 'be operated is decreased.

lVhen pinion 3 is rotated in the counterclockwise direction, as indicated in Fig. 1, pawl 5 is engaged by the ratchet teeth 4, and the plate 6 together with spindle 1, flyweights 7 and associated parts are rotated in the same direction.

It will be noted that the friction studs 9 move in advance of the pivots 8 of their respective fly-weights.

The governor is adjusted to run at a predetermined maximum speed by tensioning the retractile spring 13. At the predetermined maximum speed, the centrifugal force is sufficient to throw the fly-weights outwardly in opposition to the retractile spring, to such an extent that the friction studs 9 just-fail to make contact with the internal annular surface of the cup-shaped member 2. The slightest additionalincrease in speed is sufiicient to cause the friction studs to engage the aforementioned internal annular surface.

Fig. 3 will now be referred to and it will be assumedthat the governor is rotating at a speed which is just a. trifle in excess of its maximum predetermined speed. Now any tendency to increase the speed of the governor is, of course, due to a corresponding increasein the driving force, and this increased driving force acts on the friction stud along the line B-C. If the angle between the line B-C and the radial line A 1) be assumed to have a value a, then when tan a is equal to the coeflicient of fric tion between the friction stud and the internal annular surface of the cup-shaped member, any increase in the driving force applied to the governor, in excess of that required to drive it. at its predetermined maximum speed, will be overcome by an equal retarding force. This condition is expressed by the following equation:

tan (ZZZ where Z: coeflicient of friction a: angle indlcated in Fig.

Now assume an arbitrary increase in driving force beyond. that necessary to drive the governor at its maximum predetermined speed and let such increase be represented in direction and intensity by the line BE. It is evident that the force BE has a normal component BD and a tangential compo nent BF, and the latter represents the increasein tangential force tending to increase the speed of the governor. The tangential frictional retarding force acting on the stud 9 is equal to the product of the normal force 15D and the coeflicient of friction. lhen if such product, which isrepresented as ED, is equal and opposite to the force BF, it is obvious that the two forces are balanced and there can be no increase in speed. This condition may be expressed by the following formula:

BD Z:ED :retarding force and since BD tan czzBF:

increase in tangential driving force tan azZ If the studs 9 are made of cork and the cup shaped member 2 is made of brass, the cocilicient of friction is approximately .36 and the angle would, therefore, be approximately 19 50 because the tangent of that angle is approximately .36. With the studs 9 properly located in accordance with the theory propounded above, the speed of the governor cannot be increased beyond the predetermined maximum and experiment has shown that'it will run smoothly in spite of any inordinate driving force.

If the studs are 'solocated that the tangent of the angle a exceeds the coellicient of friction, the governor can be torcedbegvond its predetermined maximum' speed, but if'the deviation is slight, the increase in speed is very small as compared with theextra force exerted. If the studs-are so located that the tangentof the angle a is less than the coeflicient of friction, the'governor willslow down whenever ane'xcessive driving force is applied to it. I This deviation, if slight, does not appreciably affect the accuracy of the governor,

It is commercially impracticable to 105 cate the friction studs exactly at the ideal point whereby the governor is entirely unaffected by an excessive driving force, but a small deviation from the ideal point, such as would have to be allowed in commercial practice, does not sensibly affect the ultimate result.

It has been found that the friction studs can be located on a commercial basis with a degree of accuracy well within the re quirements for use in calling devices for automatic telephone practice.

As a matter of convenience, the angle ais referred to in the claims, hereinafter, as the angle of application.

l/Vhat is claimed is:

1: In a centrifugal governor, a stationary member having an annular-surface, a rota table member comprising a pivoted flyweight, said fly-weight being arranged to frictionally engage the annular surface of said stationary memberat a point in advance of the pivotal point of said fly-weight, the angle of application of the driving force being such that the tangent of said angle is Substantially equal to the coeflicient of fric tion between said fiy-weight and said stationary member. i

2. A centrifugal governor comprising a stationary member having an internal annular surface, a rotatable spindle in co-aXial alignment with said stationary member, said rotatable spindle comprising a pair of pivoted fly-weights, a friction stud on each of said fly-weights arranged to engage said internal annular surface, a pliable arm attachedto at least one of said fly-weights, a

arm, means for imparting rotary motion from said spindle to said fly-weights in only such direction that said friction studs move in advance of the pivotal points of their respective fly-weights, the angle of application of the driving force being such that the a tangent of said angle is substantially equal to the coefficient of friction between the flyweights and the stationary member.

3. A centrifugal governor comprlsmg a stationary member having an-annular surface, a rotatablemember comprising'a flyweight, a fEIlClllOllStLlCl for frictionally engaging said annular surface and s0 placed upon the fly-weight that any driving force in excess of that required to maintain a predetermined speed of operation is substantially opposed by the frictional retarding force. i

4. A centrifugal'governor comprising a stationary member having an internal annular surface, a rotatable member comprising a fly-weight, afriction stud for frictionally engaging said annular surface and'so placed upon the fiy-weight that any driving force in excess of that required to maintain apredetermined speed of operation is substantially opposed by frictional retarding force, and a retractile spring for said fly weight adjusted. to balance the centrifugalforce operating thereon at said predetermined speed so that said friction stud just fails tomake contact with the interval a11- nular surface of said stationary member.

In witness whereof, l: hereunto subscribe my name this QAth day of September, A. D.

CHARLES J, HENDRIOKSON. 

